As we build up light rays, the shape of the envelope begins to emerge. The only difference between this diagram and the physical system is that here, the overlap makes a dark envelope, whereas in the cup the overlap makes a bright envelope
More from Chalkdust
Treating the differential with discretion
Sophie Bleau explores the differential on Morseback.
In conversation with Matt Parker
Interviewing Matt was a mistake
The sieve of Eratosthenes: revisited
How can we teach people about the sieve in a way that helps them best understand prime numbers?
Creating hot ice
We created hot ice from scratch, a solution that remains liquid even below its freezing point!
Curiouser and curiouser!
Some surprising mathematical facts
Find your perfect partner
Find your perfect partner with this wonderful tree diagram!